Radar sensor platform

ABSTRACT

A radar sensor platform for clearance measurement in a vehicle has at least four radar sensors, an input being entered if necessary using an input device indicating that a width measurement of a parking space is desired and the four radar sensors then enlarging their horizontal beam angle and the arrangement for acoustic and/or visual output emitting a signal as a function of the measurement of the parking space width. This signal is, for example, the parking space width or a warning. The horizontal beam angle for the parking space measurement is at least 170°. The side clearances of the vehicle in the parking space may also be displayed. Furthermore, centered parking is possible using the acoustic and visual aids. The radar sensor platform may be installed either in the front and/or rear of the vehicle.

BACKGROUND OF THE INVENTION

The present invention is directed to a radar sensor platform.

Radar sensor platforms using a 24 gigahertz pulse frequency may be usedto detect objects at a short range, for precrash sensing, as a parkingassistant for automatic proximity radar, for blind spot detection andfor pedestrian recognition, as well as for measuring parking spaceswhile driving past the spaces.

German Published Patent Application No. 38 44 340 A1 describes a systemwhich is suitable to measure a parking space. An output unit is providedwhich informs the driver concerning an optimally calculated path of thevehicle into the parking space and emits acoustic instructions for thenew momentary steering maneuver or visual instructions. In addition, theoutput unit warns against collisions with parked motor vehicles onrequest. European Published Patent Application No. 936 471 describes anautomatic changeover to a smaller observation subrange, i.e., a beamnarrowing in a radar sensor platform. This occurs at roughly rightangles to the side of the vehicle. British Published Patent ApplicationNo. 2309555 describes a switchover from a long-range radar having anarrow beam angle to a different sensor system, namely an ultrasonicsystem having a constant beam angle and short range. Furthermore,International Published Patent Application No. WO 91/09323 describes aradar system in which the beam divergence is changed as a function ofspeed. Moreover, German Published Patent Application No. 38 13 083describes a calculation of data to control a parking operation.

BRIEF SUMMARY OF THE INVENTION

The radar sensor platform according to the present invention allowsprecise measurement of the minimum width of a parking bay or parkingspace. This measured result is displayed to the driver digitally. Thepresent invention therefore eliminates subjective width estimationerrors of parking spaces. Instead of a direct display, acoustic and/orvisual warnings may inform a driver if the parking space is suitable forparking. The intensity of the warning may be increased if the parkingspace becomes increasingly narrower.

The horizontal beam angle which is used for measuring the width of aparking space may be at least 170°. This ensures an exact measurement ofthe parking space.

In addition, a vehicle-specific threshold value for the parking spacewidth may be stored in a memory which may be linked to a processorwherein this threshold value together with the measured width of theparking space determines the output by the acoustic and/or visual outputarrangements.

Moreover, the measured parking space width may be shown on a display sothat a driver is able to utilize this information directly. It isadditionally possible to expand this by also displaying the spaces nextto the vehicle.

Moreover, the acoustic and visual outputs may be activated by theprocessor to allow centered parking. It is possible to expand thisfunction by ensuring an optimum utilization of a parking lot byspecifying distances that must be maintained from the neighboringvehicles. Finally, the radar sensor platform may be installed in atleast the front or the rear of the vehicle to ensure an optimum functionof the radar sensor platform.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Exemplary embodiments of the invention are illustrated in the drawingand are explained in greater detail in the following description.

FIG. 1 is a schematic view of a parking situation.

FIG. 2 is a block diagram of the radar sensor platform according to thepresent invention.

FIG. 3 is a flow diagram of a method according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Since an increasing number of motor vehicles with a more or lessunchanging number of available parking areas is causing optimum parkingto become an increasingly more difficult undertaking, it is necessary toprovide a driver with automatic assistance with parking in order to makethe parking operation safer and more efficient. According to the presentinvention, a radar sensor platform is proposed, which is used to measurethe distance of a parking space from a vehicle. Four radar sensors areused in particular in this case, the external radar sensors being usedprimarily to increase the horizontal beam angle to at least 170°. Thisis in particular advantageous for the measurement of parking spaces.

The radar sensor used in this exemplary embodiment operates at afrequency of 24 gigahertz, which is in particular suitable for shortrange selection since this frequency exhibits high attenuation in theatmosphere. Such radar sensors are therefore also often described asshort range radar sensors. The vertical beam angle of these radarsensors is 20°. Normally, a horizontal beam angle of 140° is used forprecrash sensors, for example.

FIG. 1 illustrates a schematic view of a parking situation. A driver ofa vehicle 1, having four radar sensors 6 at the front of the vehicle,desires to park and has selected parking space 2 for this purpose.Parking space 2 is situated between parked vehicles 3 and 4. Radarsensors 6 are aligned to cover a horizontal beam angle of 170°, which isindicated by the dashed lines. The dashed lines are limited by an arc ofa circle which defines the range of the radar sensors. Based on themeasurement of radar sensors 6, a processor in vehicle 1 determines thatparking space 2 is too narrow. Therefore it is not possible for vehicle1 to park there. Precious time is saved and a parking attempt that mightend in damage is not initiated. Both external radar sensors 6 and otherradar sensors 6 in the center may be adjustable. An electronicadjustment in particular allows an increase in the beam angle, which isnormally 140° for the precrash sensors, to 170°.

FIG. 2 illustrates a radar sensor platform of the present invention withconnected devices as a block diagram. A radar sensor platform 27 hasfour radar sensors 6, to each of which control modules 7, 8, 9 and 10are connected. These control modules 7, 8, 9 and 10 are used for bothelectrical and electromechanical control. Electromechanical control is,in particular, intended to change the horizontal beam angle. Electroniccontrol includes providing the microwaves that are required for theradar sensing and also the reception of the microwaves reflected by theobstacle.

The data inputs/outputs of control modules 7, 8, 9 and 10 are connectedto corresponding first, second, third, and fourth data inputs/outputs ofa processor 11 via particular data inputs/outputs. A bus connection isalso possible in this case. A fifth data input/output of processor 11 isconnected to a memory 12, which is used for intermediate storage ofresults as well as a permanent memory for threshold values. A first dataoutput of processor 11 is connected to an actuator 13, which isconnected to an input of a display 14. A second data output of processor11 is connected to an audio controller 15, which is connected to oneinput of a speaker 16. Controller 13 ensures that data coming fromprocessor 11 is properly shown on a display 14. The value in this caseis 3 meters. Audio controller 15 converts the signals from the processorinto analog audio signals, amplifies them and then uses speaker 16 forthe acoustic rendering. Processor 11 is connected via a data input to asignal processing unit 28, to which input device 29 is also connected.Input device 29 is positioned in the passenger compartment of vehicle 1and a driver indicates an intention to measure a parking space via thisinput device 29. This intention is then forwarded to processor 11 viasignal processing unit 28. Buttons as well as a voice control may beused as input device 29.

As a function of the inputs entered using input device 29, processor 11activates radar sensors 6 via controllers 7, 8, 9 and 10 to increase thehorizontal beam angle of radar sensors 6, if necessary, duringmeasurement of a parking space. As a function of the measuring signals,processor 11 emits signals to the driver via display 14 and speaker 16.The pulse radar method is used for the measurement in this case. The useof a Doppler method, however, is also possible. In the pulse radarmethod, time that has elapsed from the instant when a pulse is sentuntil it returns after having been reflected by the object is measured.From this it is then possible to determine the distance to the object.The use of more than four radar sensors 6 is also possible, which will,if necessary, improve the resolution. If processor 11 has determined theparking space measured by radar sensors 6, processor 11 is able todetermine therefrom the distance to vehicles 3 and 4. If the width ofthe parking space is smaller than the vehicle width of vehicle 1, whichprocessor 11 determines by making a comparison with a vehicle-specificthreshold value stored in memory 12, the driver is warned via speaker 16and display 14 that it is not possible to park the parking space. If,however, the parking space is wide enough, then the driver is able tomake a selection via input device 29 that he/she would like to park inthe center of the space. Processor 11 then assists the driver in doingso by the measurement using radar sensors 6 and the output via speaker16 and display 14, processor 11 instructing the driver using appropriatevisual and acoustic signals that he/she must always stay in the centerbetween vehicles 3 and 4. This creates a control loop in which thedriver is the actuator mechanism and the radar sensor platform is themeasuring unit.

However, the driver is also free to park in another manner, such asnon-centered. In doing so, the side clearances to obstacles 3 and 4 areshown to the driver via display 14.

A flow diagram of the method of the present invention is illustrated inFIG. 3. In step 17, a driver uses input device 29 to switch on theparking space width measurement. In step 18, processor 11 sets radarsensors 6 to a wider horizontal beam angle of 170° and processor 11loads the algorithm for parking space measurement. This algorithm islocated in memory 12.

The corresponding vehicle-specific threshold values indicate whichparking space vehicle 1 is able to use. In step 19, radar sensors 6measure the distances and processor 11 analyzes the radar sensorsignals. The distances in the parking space are thus known. In step 20,the width of the parking space is calculated therefrom. In step 21, thiswidth is compared with the minimum width required to park vehicle 1using the vehicle-specific threshold value. If the width is greater thanthis threshold value, then a continued display in step 23 indicates thatit is possible to park vehicle 1 in parking space 2. The minimumdistances of 0.5 meters, for example, to vehicles 3 and 4 parked to thesides is included in the calculation. If, however, the parking space istoo narrow, then it is indicated in step 22 that parking space 2 is notsuitable for parking vehicle 1. In doing so, numerical data may beentered, permitting the driver to possibly attempt to park nonethelessif the vehicle fits and the side clearances to vehicles 3 and 4 are lessthan half a meter. In step 24, if parking is shown to be possible instep 21, a query is made whether the driver intent is to park in thecenter. The driver then enters this using input device 29, the driverbeing assisted by speaker 16 and display 14 to park in the center of theparking space in step 25. If the driver does not desire to park in thecenter, this function is not used in step 26. The driver is then warnedof minimum distances to vehicles 3 and 4 during parking.

1. A radar sensor platform in a vehicle to perform a measurement of aparking space width, the radar sensor platform being connected to aprocessor that controls the outputting at least one of an acousticwarning and a visual warning, the radar sensor platform comprising: atleast four radar sensors configured on one side of the vehicle; and aninput device to activate the measurement of the parking space width;wherein in the event of the activation of the measurement of the parkingspace width, the at least four radar sensors are electronically adjustedto increase a horizontal beam angle as compared to another horizontalbeam angle of the at least four radar sensors when used as precrashsensors, and the outputting of the at least one of the acoustic warningand the visual warning is a function of the measurement of the parkingspace width.
 2. The radar sensor platform according to claim 1, whereinthe horizontal beam angle is at least 170°.
 3. The radar sensor platformaccording to claim 1, wherein a vehicle-specific threshold value for theparking space width is stored in a memory which is connected to theprocessor, and the arrangement for outputting the at least one of theacoustic warning and the visual warning emits the signal as a functionof a comparison of the threshold value with the measured parking spacewidth.
 4. The radar sensor platform according to claim 1, wherein thearrangement for outputting the at least one of the acoustic warning andthe visual warning includes a display configured to display the measuredparking space width as the signal.
 5. The radar sensor platformaccording to claim 4, wherein side clearances of the vehicle in aparking space are displayed.
 6. The radar sensor platform according toclaim 1, wherein the processor controls the arrangement for outputtingthe at least one of the acoustic warning and the visual warning to allowcentered parking.
 7. The radar sensor platform according to claim 1,wherein the radar sensor platform is installed in at least one of afront and a rear of the vehicle.
 8. A system to perform a measurement ofa parking space width for a vehicle, comprising: an input arrangement toactivate the measurement; and at least four radar sensors arranged onone side of the vehicle, wherein in the event of the activation of themeasurement of the parking space width, the at least four radar sensorsare electronically adjusted to increase a horizontal beam angle ascompared to another horizontal beam angle of the at least four radarsensors when used as precrash sensors, and the outputting of the atleast one of the acoustic warning and the visual warning is a functionof the measurement of the parking space width.
 9. The system accordingto claim 8, wherein the system is connected to a processor to output atleast one of an acoustic warning and a visual warning as a function ofthe measurement of the parking space width when the measurement isactivated.